Hi,
At present, compiling VMD for the Oculus Rift is a complex task in large
part becase Oculus dropped support for their Linux SDK 18 months ago.

To date I have been using OpenHMD to talk to the on-board gyrometers and
accelerometers of the Oculus HMDs, and I implemented the lens distortion
correction into a special renderer in VMD. This was necessary to support
the development of early research prototype implementations of VMD remote
visualization technologies for (Linux-based) clouds/clusters/supercomputers
displaying to a locally attached HMD. While all of this does work, it is
currently complex to build, and it's probably not what you're after if
you just want to run VMD locally, directly displaying to an HMD. I'm still
developing a cross-platform HMD management approach for VMD that will
work both for the Oculus Rift HMDs as well as the HTC Vive, and others.
That work is in very early stages and not ready for use yet.

To my knowledge FreeVR doesn't yet have support for the commodity HMDs
for the same reasons I describe with VMD itself above. The only VR toolkit
that I know of that has gotten very far here is VRUI by Olviver Kreylos,
and he's still in the early stages too. The viability of various of these
approaches also differs greatly depending on whether you're using
Linux, MacOS, or Windows, we're still in a "Wild West" period with the
software SDKs and APIs for commodity HMDs.

If you feel brave and want to try VMD with an Oculus DK2 HMD on
Linux and you have two or more very powerful NVIDIA GPUs,
I can probably walk you through the process.